Over the last weeks there has been a slew of books, articles and even a TV sitcom commemorating the victorious fight for women's votes, leading up to the centenary of Emily Wilding Davison's protest at the Epsom Derby. But one name has been singularly missing: that of the person who impeded women getting the vote for seven long years, Mrs Humphry Ward, as she defiantly called herself.

"Ma Hump", as satirists called her, came into public life with impeccable liberal credentials. A self-made woman, she was the highest earning novelist in England after the success of her 1888 novel of faith and doubt, Robert Elsmere. William Gladstone, no less, gave it a 10,000-word review, and publishers queued up to give her £10,000 for her next novel. Her uncle, Matthew Arnold, was the high priest of cultural liberalism. Another uncle, William Forster, was responsible for the Universal Education Act 1870, which rendered Britain's children minimally literate and numerate.

Newly married in Oxford to Humphry (then a progressive don), Mary Ward launched the "lectures for women" programme. It was the stepping stone to university entrance for her sex. Mary's much-loved brother, William Arnold, was a leader writer on the Guardian and a particular favourite of CP Scott. Her favourite nephew was Aldous Huxley (named after the hero of one of her novels).

Ma Hump's influence is felt even today. Inspired by the American example she set up the play centre for children movement, which enabled lower-class women in menial jobs to work full-time. She successfully pressed parliament for decent educational provision for invalid children. Other authors have left blue plaques round London. Ma Hump left the Mary Ward Centre, which still does good works in Queen's Square.

Mrs Humphry Ward's ticket to oblivion began in 1908, when a hardcore of parliamentarians, alarmed by the growing support for votes for women, decided it would be a demon wheeze to set up a Women's National Anti-Suffrage League. They needed a figurehead and invited Mrs Ward, now at the height of her Edwardian eminence. Fatally for her, she accepted.

Initially the ploy was hugely successful. It enabled successive governments to back-burner any extension of the franchise with an airy, "the most sensible of our women do not want the vote". Ward spoke, indefatigably, all over the country at public meetings, ignoring the disruptions of suffragette stink-bombs and heckling. She drummed up hundreds of thousands of female signatures petitioning against any extension.

Two men were her frontline weapons of war. Her husband, by then a senior Times journalist, reinforced that newspaper's resolute "anti" stance. And her son, Arnold, whom she got into parliament, introduced a series of "anti-suffrage" amendments which effectively clogged any move to reform.

Why did Mrs Humphry Ward do it? Not all her reasons were discreditable. She wanted IOUs from men in power to get further measures for her children's causes. She honestly, if wrongly, saw the suffragettes (the "physical forcers" of the suffrage campaign) as terrorists, Fenians in skirts. The Oscar Wilde scandal was still suppurating. She, like other "antis", had dark doubts about the suffragettes' "womanliness".

The fact that there were lesbians among the suffragette activists horrified her. Most powerful on the platform was her appeal to "patriotism". The empire depended on men's willingness to sacrifice their lives for their country. Women were required to make no such sacrifice. The vote was the male sex's payoff.

Her short-term tactical success, in helping keep any reform in a permanent "may happen one day but not now" limbo, cost her dearly. Worse than even being condemned as a traitor to her sex, she has been rendered in effect historically invisible.

She did harm. But every mother who drops her child off at a play centre before going to work, or takes her special needs child to school, or makes an appointment at the Mary Ward clinic for legal advice, or enrols for one of the centre's excellent courses, should mutter a silent benediction for Ma Hump, a wrong-headed but well-intentioned woman. And some of the novels are pretty good, too.

A hundred years ago, three suffragettes ran through Manchester Art Gallery, smashing the glass on pictures. The words they used to explain their actions remain as relevant today, writes Jeanette Winterson